At this point, DRG should, from a mechanical perspective, be merged in with MNK and SAM. The job already has more HP than the other two at the same VIT level and as was stated, the higher physical defense is a remnant of 2.0 where DRG had higher physical and lower magical defense compared to it's melee counterpart, MNK. At this point the magical defense has been normalized between the two jobs leaving the only difference between the two the level of physical defense.

Additionally, you could merge NIN gear in with BRD and MCH as all use DEX as a main stat. I believe previously the aiming gear had lower defensive stats than the scouting gear, but that's also no longer the case.

I get the argument regarding allowing the developers to create unique aesthetics for the jobs being the reason they're separate, but let's be honest. How often do they actually do this verses how often are the striking and scouting gear color swaps of each other, same with the aiming and scouting, or fending and maiming... they often create fewer distinct models than classes of armor already. The job-specific armor can still function to provide a unique look for the individual jobs.